#include "HD44780.h"

#include <stdio.h>
#include <string.h>
#include <inttypes.h>
#include "WProgram.h"

// When the display powers up, it is configured as follows:
//
// 1. Display clear
// 2. Function set: 
//    DL = 1; 8-bit interface data 
//    N = 0; 1-line display 
//    F = 0; 5x8 dot character font 
// 3. Display on/off control: 
//    D = 0; Display off 
//    C = 0; Cursor off 
//    B = 0; Blinking off 
// 4. Entry mode set: 
//    I/D = 1; Increment by 1 
//    S = 0; No shift 
//
// Note, however, that resetting the Arduino doesn't reset the LCD, so we
// can't assume that its in that state when a sketch starts (and the
// HD44780 constructor is called).

HD44780::HD44780(uint8_t rs, uint8_t enable,
  uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
  uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7) :
  _four_bit_mode(0), _rs_pin(rs), _enable_pin(enable)
{
  _data_pins[0] = d0;
  _data_pins[1] = d1;
  _data_pins[2] = d2;
  _data_pins[3] = d3; 
  _data_pins[4] = d4;
  _data_pins[5] = d5;
  _data_pins[6] = d6;
  _data_pins[7] = d7; 
  
  pinMode(_rs_pin, OUTPUT);
  pinMode(_enable_pin, OUTPUT);
  
  for (int i = 0; i < 8; i++)
    pinMode(_data_pins[i], OUTPUT); 
}

HD44780::HD44780(uint8_t rs, uint8_t enable,
  uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3) :
  _four_bit_mode(1), _rs_pin(rs), _enable_pin(enable)
{
  _data_pins[0] = d0;
  _data_pins[1] = d1;
  _data_pins[2] = d2;
  _data_pins[3] = d3; 
  
  pinMode(_rs_pin, OUTPUT);
  pinMode(_enable_pin, OUTPUT);
  
  for (int i = 0; i < 4; i++)
    pinMode(_data_pins[i], OUTPUT);
}

void HD44780::init()
{
  delay(20);  // Wait LCD get ready
  
  // Initialize LCD by instruction
  if(_four_bit_mode)
  {
    sendNibble(0x03, LOW);
    delay(5);
    sendNibble(0x03, LOW);
    delayMicroseconds(100);
    sendNibble(0x03, LOW);
    delayMicroseconds(100);
    sendNibble(0x02, LOW);
    
    command(0x28);  // function set: 4 bits, 1 line, 5x8 dots
    command(0x0C);  // display control: turn display on, cursor off, no blinking
    command(0x06);  // entry mode set: increment automatically, display shift, right shift
    clear();
  } else {
    command(0x30);
    delay(5);
    command(0x30);
    command(0x10);
    
    command(0x38);  // function set: 8 bits, 1 line, 5x8 dots
    command(0x0C);  // display control: turn display on, cursor off, no blinking
    command(0x06);  // entry mode set: increment automatically, display shift, right shift
  }
  
  clear();
}

void HD44780::clear()
{
  command(0x01);  // clear display, set cursor position to zero
  delayMicroseconds(2000);
}

void HD44780::home()
{
  command(0x02);  // set cursor position to zero
  delayMicroseconds(2000);
}

void HD44780::setCursor(int col, int row)
{
  int row_offsets[] = { 0x00, 0x40, 0x14, 0x54 };
  command(0x80 | (col + row_offsets[row]));
}

void HD44780::command(uint8_t value) {
  send(value, LOW);
}

void HD44780::write(uint8_t value) {
  send(value, HIGH);
}

void HD44780::send(uint8_t value, uint8_t mode) {
  digitalWrite(_rs_pin, mode);

  if (_four_bit_mode) {
    sendNibble(value >> 4, mode);
    sendNibble(value & 0x0f, mode);
  } else {
    for (int i = 0; i < 8; i++) {
      digitalWrite(_data_pins[i], (value >> i) & 0x01);
    }

    digitalWrite(_enable_pin, HIGH);
    digitalWrite(_enable_pin, LOW);
  }
  
  delayMicroseconds(100);
}

void HD44780::sendNibble(uint8_t value, uint8_t mode)
{
  for (int i = 0; i < 4; i++) {
    digitalWrite(_data_pins[i], (value >> i) & 0x01);
  }

  digitalWrite(_enable_pin, HIGH);
  digitalWrite(_enable_pin, LOW);
}